1. Field of the Invention
The present invention relates to vegetated roofs and to recycling of rain water.
2. Discussion of Related Art
A prior art search revealed the following patents as possibly being relevant to the instant invention: U.S. Patent Application Publication Nos. 2002/0007591 and 2007/0094927.
The conversion of vegetated areas to roads and buildings, e.g., development, has a number of adverse impacts, which are particularly noticeable as development density increases. For example, transevaporation is the natural cooling effect that occurs as water, deriving from rainfall, for example, evaporates back into the atmosphere. Development reduces this cooling effect because rain falling on a building or road is quickly funneled into storm sewers. Further, the substitution of darkly colored roads and roofs for the vegetation absorbs heat, and these two phenomena contribute to the so-called “heat island” effect. This effect is more pronounced in summer than in winter, just when it is not wanted, because the sun is higher in the sky. As a result, the cooling requirements for a building subject to the heat island effect are greater than they would be otherwise, resulting in greater operating costs and the possible generation of greenhouse gases associated with the requirements for the generation of the additional electricity to cool the building.
Another problem, particularly noticeable with high density development, is water consumption. Water for drinking, that is “potable” water, is only a small fraction of the total amount consumed by a person in a developed country. Other non-drinking uses include bathing, washing clothes, dishes and cars. These other uses do not require that the water be potable; that is, the water can be so-called “gray” water. Nevertheless, most people get their water from a well or from a municipal water company, the entire quantity of which typically is potable.
The advent of so-called “vegetated roofs” has a number of benefits, such as reducing the heat island effect, and possibly providing food and an aesthetically pleasing view. However, up to now there has been no effort to store the excess rainfall not used by the vegetation of the vegetated roof. Further, during drought periods, unless the vegetation can be allowed to die or to go dormant, it will need to be watered with fresh water, usually deriving from a municipal water system, which often derives from underground aquifers. In many areas, heavy reliance on the aquifer as a source of domestic use water is noticeably, and in some cases, severely depleting the aquifer.
The instant invention is intended to address these problems.